The runoff in the middle of yellow river to the sea has decreased 10×109 m3 per year between 1980 and 1999 compared 1950 and 1969,and the sediment load delivered from the yellow river to the sea has decreased 0.5×109t per year.Based on SWAT (soil and water assessment tools) model,study on hydrological processes response to land use/cover and climate change is great important.Through the researches,the result indicated that the SWAT was a powerful tool to simulate the effect of environmental change on the surface runoff.The Nash-Sutcliffe model (Ens) ,and the coefficient of determination (R2) for monthly flow were 0.89 and 0.75 during the calibration periods and 0.85 and 0.70 during the validation periods,respectively.